Ala. Code § 25-9-281: Safety Devices and Practices for Compressed Air Receivers, Etc.

(a) All compressed air receivers, cylinders, or other vessels used in or around surface mining operations shall be protected by safety or relief valves to insure safe operation. All oxygen, acetylene, or similar compressed gas cylinders shall comply with manufacturer’s recommendations.

(b) Safety or relief valves shall be tested once each operating day.

(c) All compressed air receivers, tanks, etc., shall be equipped with a drain valve and a pressure gauge.

(d) Drain valves shall be operated at least once each operating day.